Post-deposition cleaning methods and formulations for substrates with cap layers

ABSTRACT

One embodiment of the present invention is a method of fabricating an integrated circuit. The method includes providing a substrate having a metal and dielectric damascene metallization layer and depositing substantially on the metal a cap. After deposition of the cap, the substrate is cleaned with a solution comprising an amine to provide a pH for the cleaning solution of 7 to about 13. Another embodiment of the presented invention is a method of cleaning substrates. Still another embodiment of the present invention is a formulation for a cleaning solution.

CROSS REFERENCES

The present application is a divisional of U.S. patent application Ser.No. 12/334,462, titled “POST-DEPOSITION CLEANING METHODS ANDFORMULATIONS FOR SUBSTRATES WITH CAP LAYERS,” to KOLICS et al., filedDec. 13, 2008, projected issue date Mar. 26, 2013, projected U.S. Pat.No. 8,404,626. This application claims benefit of U.S. PatentApplication Ser. No. 61/016,427, Docket No. XCR-009, titled“POST-DEPOSITION CLEANING METHODS AND FORMULATIONS FOR SUBSTRATES WITHCAP LAYERS” to KOLICS et al., filed Dec. 21, 2007. U.S. patentapplication Ser. No. 12/334,462 (U.S. Pat. No. 8,404,626) and U.S.Patent Application Ser. No. 61/016,427 are incorporated herein, in theirentirety, by this reference.

BACKGROUND

This invention pertains to fabrication of electronic devices such asintegrated circuits; more specifically, this invention relates tomethods and formulations for cleaning substrates having cap layerscontaining at least one of the chemical elements cobalt and nickel onmetal and dielectric damascene metallization structures.

Cleaning of surfaces having heterogeneous compositions is challenging.This is particularly true in situations such as for surfaces that aresubject to corrosion and such as surfaces having different corrosionrates for the heterogeneous compositions. The problem is greater stillfor surfaces having thin film layers such as layers used in fabricatingelectronic devices. For electronic device fabrication, surfaces havingfilms around 20 nm thick need to be cleaned while avoiding degradationof the surface quality and thickness of the films.

In a specific case, a metal cap is applied to copper interconnects thatare embedded in a dielectric structure to form a damascene metallizationlayer. In order to provide good electrical performance such as lowleakage current with good yield, high breakdown voltage and timedependent dielectric breakdown, the surface of the metal cap and thesurface of the dielectric area are preferably cleaned so as to removecontaminants and defects. During this treatment, the metal cap shouldnot suffer significant metal loss, or experience pitting or other formsof localized corrosion. Examples of materials for the metal cap arematerials such as cobalt, cobalt alloy, cobalt-nickel alloy, nickel, andnickel alloy. In addition, defects such as particles and residues haveto be removed from the entire wafer.

There is a need for cleaning solutions and methods of cleaningsubstrates that can be used to fabricate electronic devices. Morespecifically, there is a need for improved solutions and methods thatcan meet the requirements for such devices.

SUMMARY

This invention pertains to fabrication of electronic devices. Oneembodiment of the present invention is a method of fabricating anintegrated circuit. The method includes providing a substrate having ametal and dielectric damascene metallization layer and depositingsubstantially on the metal a cap. After deposition of the cap, thesubstrate is cleaned with a solution comprising an amine to provide a pHfor the cleaning solution of 7 to about 13. Another embodiment of thepresented invention is a method of cleaning substrates. Still anotherembodiment of the present invention is a formulation for a cleaningsolution.

It is to be understood that the invention is not limited in itsapplication to the details of construction and to the arrangements ofthe components set forth in the following description or illustrated inthe drawings. The invention is capable of other embodiments and of beingpracticed and carried out in various ways. In addition, it is to beunderstood that the phraseology and terminology employed herein are forthe purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods, and systems for carryingout aspects of the present invention. It is important, therefore, thatthe claims be regarded as including such equivalent constructionsinsofar as they do not depart from the spirit and scope of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow diagram of an embodiment of the presentinvention.

description

The present invention pertains to interconnect metallization that usesan electrically conductive metal with a cap and a dielectric forming adamascene metallization structure for electronic devices such asintegrated circuits. More preferably, the present invention pertains tointerconnect metallization layers that include a dielectric and a metal,such as copper, having a cap comprising one of the chemical elementscobalt and nickel for electronic devices.

The operation of embodiments of the present invention will be discussedbelow, primarily in the context of processing semiconductor wafers suchas silicon wafers used for fabricating integrated circuits. Themetallization layers for the integrated circuits include copper formetal lines with electrolessly deposited caps comprising at least one ofthe chemical elements cobalt and nickel or their alloys formed intodamascene or dual damascene dielectric structures. Optionally, thedielectric is a low k dielectric material such as a carbon doped siliconoxide (SiOC:H). However, it is to be understood that embodiments inaccordance with the present invention may be used for othersemiconductor devices, metals other than copper, and wafers other thansemiconductor wafers.

Reference is now made to FIG. 1 where there is shown a process flow 20for fabricating electronic devices according to one embodiment of thepresent invention. Process flow 20 includes providing a substrate havinga metal and dielectric damascene metallization, step 25. Process flow 20also includes using electroless deposition to deposit on the metal a capcomprising at least one of the chemical elements cobalt and nickel, step35. After step 35, process flow 20 includes cleaning the substrate witha cleaning solution comprising an amine to provide a pH of 7 to 13 forthe cleaning solution, step 40. More specifically, the amine is capableof raising the pH of the cleaning solution to a value in the range of 7to 13 and all values and subranges subsumed therein. As an option, thecleaning solution may comprise two or more amines and at least one ofthe two or more amines is capable of raising the pH of the cleaningsolution to a value in the range of 7 to 13 and all values and subrangessubsumed therein. According to a preferred embodiment of the presentinvention, the pH of the cleaning solution is a value from about 8 toabout 11.5.

Numerous compounds are suitable for use as the amine in embodiments ofthe present invention. A list of suitable compounds for amines forembodiments of the present invention includes, but is not limited to,primary alkylamines; secondary alkylamines; tertiary alkylamines;quaternary alkylamines; primary arylamines; secondary arylamines;tertiary arylamines; quaternary arylamines; ammonia; primaryalkanolamines; secondary alkanolamines; tertiary alkanolamines such asethanolamine, diethanolamine, triethanolamine, choline; amines withmixed alkyl and alkanol functionalities; tetramethylguanidine;hydroxylamine; and combinations thereof. Amine molecules usually havethe general formula R_(3-x)NH_(x) where R is a hydrocarbon and 0≦x≦3.Some embodiments of the present invention include one or more aminespresent in the cleaning solution in amounts ranging from about 1 gramper liter to about 100 grams per liter (g/L). A preferred embodiment ofthe present invention includes deionized water in the cleaning solution.

For the purpose of the present disclosure, cleaning the substrateincludes removing contaminants, removing defects, or removingcontaminants and removing defects. The composition of the cleaningsolution is selected so as to facilitate removal of defects and/orcontaminants from the surface of the substrate, more particularly thesurface of the cap and surface of the dielectric. More preferably, thecomposition of the cleaning solution is selected so as to clean thesurface of the cap and the surface of the dielectric with negligible orsubstantially no reduction in the thickness of the cap. Preferably, thethickness of the cap is reduced by less than 15% as a result of thecleaning. More preferably, the thickness of the cap is reduced by lessthan 10% as a result of the cleaning. According to one embodiment of thepresent invention, the thickness of the cap is reduced by less than 1.5nm.

Embodiments of the present invention as presented in FIG. 1 may includeusing a cleaning solution that contains one or more additionaladditives. As an option for some embodiments of the present invention,the cleaning solution further comprises one or more complexing agentsand at least one of the one or more complexing agents is not an amine.For the present disclosure, the complexing agent that is not an amine isreferred to as a non-amine complexing agent. The amine complexing agentis defined here as a chemical compound in which the only functionalgroup in the compound that forms a complex has the general formulaNRR′R″ where N is a nitrogen atom and R, R′, and R″ can be hydrogen,alkyl or aromatic groups.

Numerous compounds are suitable for use as complexing agents inembodiments of the present invention. A list of complexing agents forembodiments of the present invention includes, but is not limited to,carboxylic acids, hydroxycarboxylic acids, amino acids, phosphonic acid,phytic acid, organic acids where Ig K for CoL>2, and combinationsthereof. Some embodiments of the present invention include one or morecomplexing agents present in the cleaning solution in amounts rangingfrom about 0.5 gram per liter to about 50 grams per liter.

As an option, some embodiments of the present invention as presented inFIG. 1 may include using a cleaning solution that also contains one ormore corrosion inhibitors to substantially protect the cap film orretard the dissolution of the cap in the cleaning solution. As indicatedabove, preferred embodiments of the present invention are capable ofcleaning the substrate with negligible or substantially no reduction inthe thickness of the cap; one or more corrosion inhibitor compounds maybe included in embodiments of the present invention for that purpose.

Numerous compounds are suitable for use as corrosion inhibitors inembodiments of the present invention. A list of corrosion inhibitors forembodiments of the present invention includes, but is not limited to,triazole and its derivatives such as benzotriazole,methyl-benzotriazole, carboxy-benzotriazole, hydroxybenzotriazole;thiazole and its derivatives such as mercaptobenzothiazole;polyvinylpyrrolidone; polyvinylalcohol and its derivatives;polyalkylimines; polyethylenimines; long chain alkylamines; tetrazoles;orthophosphates; metaphosphates; phosphites; phosphonates; silicates;alkylphosphonates; alkoxysilanes, nitrites; bicyclohexylammoniumnitrite; and combinations thereof. Some embodiments of the presentinvention include one or more corrosion inhibitors present in thecleaning solution in amounts ranging from about 0.01 gram per liter toabout 20 grams per liter.

As an option, some embodiments of the present invention as presented inFIG. 1 may include using a cleaning solution that also contains one ormore oxygen scavenger compounds to remove dissolved oxygen from thecleaning solution. More specifically, the oxygen scavenger provides alower concentration of dissolved oxygen in the cleaning solution.Preferably, the amount of dissolved oxygen is kept to a minimum so as tosubstantially prevent oxidation of the cap by the dissolved oxygen.

Numerous compounds are suitable for use as oxygen scavengers fordissolved oxygen in embodiments of the present invention. A list ofoxygen scavengers for embodiments of the present invention includes, butis not limited to, hydroxylamine and derivatives such asdiethylhydroxylamine; methyl-ethylketoxime; carbohydrazide; L-ascorbicacid; D-ascorbic acid, derivatives of ascorbic acid; chlorogenic acid;hydrazine, hydrazine salts; derivatives of hydrazine; caffeic acid;phytic acid; luteolin; sulfites; and combinations thereof. Someembodiments of the present invention include one or more oxygenscavengers present in the cleaning solution in amounts ranging fromabout 0.05 gram per liter to about 10 grams per liter. Preferredembodiments of the present invention maintain concentrations ofdissolved oxygen in the cleaning solution at less than 1 part permillion (ppm). For some embodiments of the present invention, the lowlevels of dissolved oxygen are obtained by providing a sufficient amountof one or more oxygen scavengers.

As an option, some embodiments of the present invention as presented inFIG. 1 may include using a cleaning solution that also contains one ormore reducing agents. The reducing agent is selected so as to besubstantially incapable of scavenging for dissolved oxygen. Morespecifically, the reducing agent is selected so as to provide a functionother than scavenging for dissolved oxygen in the cleaning solution. Aprimary function of the reducing agent is to minimize unwanted anodicdissolution of the cap. This is done by the introduction of reducingagent in the cleaning solution. Depending on the type of reducing agent,the oxidation of these compounds is energetically more favorable thanthe oxidation and dissolution of the cap.

Numerous compounds are suitable for use as reducing agents inembodiments of the present invention. A list of reducing agents forembodiments of the present invention includes, but is not limited to,boron containing reducing agents, hypophosphites, thiosulfite,aldehydes, and combinations thereof. Some embodiments of the presentinvention include one or more reducing agents present in the cleaningsolution in amounts ranging from about 0.1 gram per liter to about 10grams per liter.

As an option, some embodiments of the present invention as presented inFIG. 1 may include using a cleaning solution that also contains one ormore surface active agents. The surface active agent is included so asto provide adequate wetting of the substrate during the cleaning.Preferably, the entire surface of the substrate is adequately wetted bythe cleaning solution so that the dielectric areas of the substrate arewetted and the cap areas of the substrate are wetted.

Numerous compounds are suitable for use as surface active agents inembodiments of the present invention. A list of surface active agentsfor embodiments of the present invention includes, but is not limitedto, anionic surface active agents, cationic surface active agents,nonionic surface active agents, amphoteric surface active agents, andcombinations thereof. Some embodiments of the present invention includeone or more surface active agents present in the cleaning solution inamounts ranging from about 0.02 gram per liter to about 2 grams perliter. Preferably, if there are two or more surface active agents theneach of the surface active agents is present in the cleaning solution inamounts from about 0.02 gram per liter to about 2 grams per liter.

As an option, some embodiments of the present invention as presented inFIG. 1 may include using a cleaning solution that also contains one ormore water-soluble solvents. The water-soluble solvent is included so asto perform tasks such as to help remove organic contaminants from thesurface of the substrate. The water-soluble solvent may also be includedso as to perform tasks such as to help dissolve one or more additivesincluded in the cleaning solution that may have a low or an insufficientsolubility in water.

Numerous compounds are suitable for use as water-soluble solvents inembodiments of the present invention. A list of water-soluble solventsfor embodiments of the present invention includes, but is not limitedto, primary alcohols, secondary alcohols, tertiary alcohols, polyols,ethylene glycol, dimethylsulfoxide, propylenecarbonate, and combinationsthereof. Some embodiments of the present invention include one or morewater-soluble solvents present in the cleaning solution in amountsranging from about 10 gram per liter to about 100 grams per liter.

As an option for some embodiments of the present invention as presentedin FIG. 1, cleaning the substrate with the cleaning solution, step 40,can be performed using a brush to apply the cleaning solution to thesubstrate. Other embodiments of the present invention can be performedthat include applying the cleaning solution to the substrate withoutusing a brush; more specifically, the cleaning solution may be appliedby methods such as dipping the substrate into the cleaning solution,such as spraying the cleaning solution onto the substrate, and such asapplying the solution using a proximity head.

According to preferred embodiments of the present invention as presentedin FIG. 1, the temperature for performing step 40, cleaning thesubstrate with a cleaning solution, is preferably in the range fromabout 5° C. to about 90° C. Preferably the temperature of the cleaningsolution is controlled. As an option the temperature of the substratemay be controlled.

Preferred embodiments of the present invention as presented in FIG. 1use a cleaning solution that also includes one or more additives such asa non-amine complexing agent substantially as described supra, acorrosion inhibitor substantially as described supra, a surface activeagent substantially as described supra, an oxygen scavengersubstantially as described supra, a reducing agent substantially asdescribed supra, and a water soluble solvent substantially as describedsupra. This means that additional embodiments of the present inventionare described by combinations of these additives provided in thecleaning solution for the process flow shown in FIG. 1. Morespecifically, the additives and combinations of the additives producecleaning solutions having dissimilar compositions that define dissimilarembodiments of the invention presented in FIG. 1. A list of additionalpreferred compositions of cleaning solutions for preferred embodimentsof the present invention as presented in FIG. 1 includes but is notlimited to the following cleaning solutions:

1. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent and an amount of corrosion inhibitor.

2. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent and an amount of oxygen scavenger.

3. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent and an amount of reducing agent.

4. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, and an amount ofoxygen scavenger.

5. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, and an amount ofreducing agent.

6. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, and an amount ofreducing agent.

7. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of reducingagent, and an amount of corrosion inhibitor.

8. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, and an amount ofsurface active agent.

9. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, and an amount ofsurface active agent.

10. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of reducing agent, and an amount of surfaceactive agent.

11. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, an amount of oxygenscavenger, and an amount of surface active agent.

12. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, an amount ofreducing agent, and an amount of surface active agent.

13. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of reducingagent, and an amount of surface active agent.

14. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of reducingagent, an amount of corrosion inhibitor, and an amount of surface activeagent.

15. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, and an amount ofwater-soluble solvent.

16. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, and an amount ofwater-soluble solvent.

17. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of reducing agent, and an amount ofwater-soluble solvent.

18. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, an amount of oxygenscavenger, and an amount of water-soluble solvent.

19. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, an amount ofreducing agent, and an amount of water-soluble solvent.

20. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of reducingagent, and an amount of water-soluble solvent.

21. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of reducingagent, an amount of corrosion inhibitor, and an amount of water-solublesolvent.

22. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, an amount of surfaceactive agent, and an amount of water-soluble solvent.

23. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of surfaceactive agent, and an amount of water-soluble solvent.

24. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of reducing agent, an amount of surfaceactive agent, and an amount of water-soluble solvent.

25. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, an amount of oxygenscavenger, an amount of surface active agent, and an amount ofwater-soluble solvent.

26. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of corrosion inhibitor, an amount ofreducing agent, an amount of surface active agent, and an amount ofwater-soluble solvent.

27. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of reducingagent, an amount of surface active agent, and an amount of water-solublesolvent.

28. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an amount of oxygen scavenger, an amount of reducingagent, an amount of corrosion inhibitor, an amount of surface activeagent, and an amount of water-soluble solvent.

29. The cleaning solution presented in FIG. 1 including a corrosioninhibitor present in a concentration between about 0.01 g/L to about 10g/L and an oxygen scavenger present in a concentration between about0.05 g/L to about 10 g/L.

30. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, a corrosion inhibitor present at a concentrationbetween about 0.01 g/L to about 20 g/L and a reducing agent present at aconcentration between about 0.1 g/L to about 10 g/L.

31. The cleaning solution presented in FIG. 1 including an amount ofcomplexing agent, an oxygen scavenger present at a concentration betweenabout 0.05 g/L to about 10 g/L, and a reducing agent present at aconcentration between about 0.1 g/L to about 10 g/L.

32. The cleaning solution presented in FIG. 1 including an amount of acomplexing agent, a corrosion inhibitor present at a concentrationbetween about 0.01 g/L to about 20 g/L, an oxygen scavenger present at aconcentration between about 0.05 g/L to about 10 g/L, and a reducingagent present at a concentration between about 0.1 g/L to about 10 g/L.

33. The cleaning solution presented in FIG. 1 including an amount ofnon-amine complexing agent, an amount of corrosion inhibitor, an amountof surface active agent, an amount of oxygen scavenger, an amount ofreducing agent, and an amount of water soluble solvent.

34. The cleaning solution presented in FIG. 1 having the amine at aconcentration from about 1 g/L to about 100 g/L and the cleaningsolution also including at least one of: an amount of non-aminecomplexing agent, an amount of corrosion inhibitor, an amount of surfaceactive agent, an amount of oxygen scavenger, an amount of reducingagent, and an amount of water soluble solvent.

35. The cleaning solution presented in FIG. 1 having the amine at aconcentration from about 1 g/L to about 100 g/L and the cleaningsolution also including an amount of non-amine complexing agent, anamount of corrosion inhibitor, an amount of surface active agent, anamount of oxygen scavenger, an amount of reducing agent, and an amountof water soluble solvent.

36. The cleaning solution presented in FIG. 1 having the amine at aconcentration from about 1 g/L to about 100 g/L and the cleaningsolution also including at least one of: a non-amine complexing agent ata concentration from about 0.5 g/L to about 50 g/L; a corrosioninhibitor at a concentration from about 0.01 g/L to about 20 g/L; asurface active agent at a concentration of 0.02 to 2 g/L; an oxygenscavenger at a concentration from about 0.05 g/L to about 10 g/L; areducing agent at a concentration from about 0.1 g/L to about 10 g/L;and a water soluble solvent at a concentration from about 10 g/L toabout 100 g/L.

37. The cleaning solution presented in FIG. 1 having the amine at aconcentration from about 1 g/L to about 100 g/L and the cleaningsolution also including a non-amine complexing agent at a concentrationfrom about 0.5 g/L to about 50 g/L; a corrosion inhibitor at aconcentration from about 0.01 g/L to about 20 g/L; a surface activeagent at a concentration of 0.02 g/L to 2 g/L; an oxygen scavenger at aconcentration from about 0.05 g/L to about 10 g/L; a reducing agent at aconcentration from about 0.1 g/L to about 10 g/L; and a water solublesolvent at concentration from about 10 g/L to about 100 g/L.

38. The cleaning solution presented in FIG. 1 having the amine at aconcentration from about 1 g/L to about 100 g/L and the amine isselected form the group consisting of primary alkylamines, secondaryalkylamines, tertiary alkylamines, quaternary alkylamines, primaryarylamines, secondary arylamines, tertiary arylamines, quaternaryarylamines, ammonia, primary alkanolamines, secondary alkanolamines,tertiary alkanolamines, ethanolamine, diethanolamine, triethanolamine,choline, amines with mixed alkyl and alkanol functionalities,tetramethylguanidine, and hydroxylamine; and the cleaning solution alsoincluding at least one of:

a complexing agent at a concentration from about 0.5 g/L to about 50 g/Lselected from the group consisting of carboxylic acids,hydroxycarboxylic acids, amino acids, phosphonic acid, phytic acid, andorganic acids where Ig K for CoL>2;

a corrosion inhibitor at a concentration from about 0.01 g/L to about 20g/L selected from the group consisting of triazole, benzotriazole,methyl-benzotriazole, carboxy-benzotriazole, hydroxybenzotriazole,thiazole, mercaptobenzothiazole, polyvinylpyrrolidone, polyvinylalcohol,polyalkylimines, polyethylenimines, long chain alkylamines, tetrazoles,orthophosphates, metaphosphates, phosphites, phosphonates, silicates,alkylphosphonates, alkoxysilanes, nitrites, and bicyclohexylammoniumnitrite;

-   -   a surface active agent at a concentration of 0.02 g/L to 2 g/L        selected from the group consisting of anionic surface active        agents, cationic surface active agents, nonionic surface active        agents, amphoteric surface active agents, and combinations        thereof;    -   an oxygen scavenger at a concentration from about 0.05 g/L to        about 10 g/L selected from the group consisting of        hydroxylamine, diethylhydroxylamine, methyl-ethylketoxime,        carbohydrazide, L-ascorbic acid, D-ascorbic acid, derivatives of        ascorbic acid, chlorogenic acid, hydrazine, hydrazine salts,        derivatives of hydrazine, caffeic acid, phytic acid, luteolin,        and sulfites;    -   a reducing agent at a concentration from about 0.1 g/L to about        10 g/L selected from the group consisting of boron containing        reducing agents, hypophosphites, thiosulfite, and aldehydes; and    -   a water soluble solvent at a concentration from about 10 g/L to        about 100 g/L selected from the group primary alcohols,        secondary alcohols, tertiary alcohols, polyols, ethylene glycol,        dimethylsulfoxide, propylenecarbonate, and mixtures thereof.

As an option for some embodiments of the present invention asrepresented in FIG. 1, any of the cleaning solution compositions, suchas the cleaning solution compositions presented supra, can be applied tothe substrate using a brush.

Alternatively, any of the cleaning solution compositions, such as thecleaning solution compositions presented supra, can be applied to thesubstrate by methods other than using a brush. Another option for someembodiments of the present invention as represented in FIG. 1, any ofthe cleaning solution compositions, such as the cleaning solutioncompositions presented supra, can be used at temperatures in the rangefrom about 5° C. to about 90° C. to clean the substrate.

As presented supra, numerous cleaning solution compositions are suitablefor embodiments of the present invention. According to a preferredembodiment of the present invention, step 40, cleaning the substrate, isperformed using cleaning solution compositions described supra and theconcentration of dissolved oxygen in the cleaning solution is maintainedat less than about 1 part per million. This means that for any of theselected cleaning solutions for embodiments of the present invention, itis preferred that the dissolved oxygen concentration in the cleaningsolution is maintained at less than about 1 part per million whencleaning the substrate.

Another embodiment of the present invention comprises a method ofcleaning a substrate for electronic devices. More specifically, it is amethod of cleaning a substrate having copper and dielectric damascenemetallization. The surface of the copper has a cap that includes cobalt,cobalt alloy, nickel, nickel alloy, or cobalt-nickel alloy. The methodcomprises applying a cleaning solution to the substrate to removedefects and/or contamination with negligible dissolution of the cap, thesolution comprises one or more amines, at least one of the one or moreamines provides a pH from 7 to 13 in the cleaning solution. According toa preferred embodiment of the present invention, the pH of the cleaningsolution is a value from about 8 to about 11.5.

For the purpose of the present disclosure, cleaning the substrateincludes removing contaminants, removing defects, or removingcontaminants and removing defects. The composition of the cleaningsolution is selected so as to facilitate removal of defects and/orcontaminants from the surface of the substrate, more particularly thesurface of the cap and surface of the dielectric. More preferably, thecomposition of the cleaning solution is selected so as to clean thesurface of the cap and the surface of the dielectric with negligible orsubstantially no reduction in the thickness of the cap. Preferably,thickness of the cap is reduced by less than 15% as a result of thecleaning. More preferably, the thickness of the cap is reduced by lessthan 10% as a result of the cleaning. According to one embodiment of thepresent invention, the thickness of the cap is reduced by less than 1.5nm.

Preferred embodiments of the method of cleaning substrates use acleaning solution that also includes one or more additives such as acomplexing agent substantially as described supra, a corrosion inhibitorsubstantially as described supra, a surface active agent substantiallyas described supra, an oxygen scavenger substantially as describedsupra, a reducing agent substantially as described supra, and a watersoluble solvent substantially as described supra. This means thatadditional embodiments of the present invention are described bycombinations of these additives provided in the cleaning solution. Morespecifically, the additives and combinations of the additives producecleaning solutions having dissimilar compositions that define dissimilarembodiments of the method of cleaning substrates. The combination ofadditives and amounts of the additives are selected so that the cleaningsolution is effective for cleaning the substrate without significantlyreducing the thickness of the cap. A list of additional preferredcompositions for preferred embodiments of the method of cleaningsubstrates includes but is not limited to the cleaning solutionsdescribed supra for embodiments of process flow 20.

Another embodiment of the present invention is a cleaning solution foran integrated circuit substrate. The cleaning solution comprises anamine at a concentration from about 1 g/L to about 100 g/L to provide apH for the cleaning solution of 7 to 13 and all values and subrangessubsumed therein. More specifically, the amine is capable of raising thepH of the solution to a value above 7 and less than about 13. Accordingto a preferred embodiment of the present invention, the pH of thecleaning solution is a value from about 8 to about 11.5. The solutionalso includes at least one additive selected from the group consistingof:

-   -   a non-amine complexing agent at a concentration from about 0.5        g/L to about 50 g/L;    -   a corrosion inhibitor at a concentration from about 0.01 g/L to        about 20 g/L;    -   a surface active agent at a concentration of 0.02 g/L to 2 g/L;    -   an oxygen scavenger at a concentration from about 0.05 g/L to        about 10 g/L;    -   a reducing agent at a concentration from about 0.1 g/L to about        10 g/L, the reducing agent having substantially no oxygen        scavenging properties; and    -   a water soluble solvent at a concentration from about 10 to        about 100 g/L.        As an alternative, the cleaning solution also includes at least        two additives selected from the group consisting of    -   a non-amine complexing agent at a concentration from about 0.5        g/L to about 50 g/L;    -   a corrosion inhibitor at a concentration from about 0.01 g/L to        about 20 g/L;    -   a surface active agent at a concentration of 0.02 g/L to 2 g/L;    -   an oxygen scavenger at a concentration from about 0.05 g/L to        about 10 g/L;    -   a reducing agent at a concentration from about 0.1 g/L to about        10 g/L, the reducing agent having substantially no oxygen        scavenging properties; and    -   a water soluble solvent at a concentration from about 10 g/L to        about 100 g/L.        As another alternative, the cleaning solution also includes at        least three additives selected from the group consisting of    -   a non-amine complexing agent at a concentration from about 0.5        g/L to about 50 g/L;    -   a corrosion inhibitor at a concentration from about 0.01 g/L to        about 20 g/L;    -   a surface active agent at a concentration of 0.02 g/L to 2 g/L;    -   an oxygen scavenger at a concentration from about 0.05 g/L to        about 10 g/L;    -   a reducing agent at a concentration from about 0.1 g/L to about        10 g/L, the reducing agent having substantially no oxygen        scavenging properties; and    -   a water soluble solvent at a concentration from about 10 g/L to        about 100 g/L.        For still another alternative, the cleaning solution also        includes at least four additives selected from the group        consisting of    -   a non-amine complexing agent at a concentration from about 0.5        g/L to about 50 g/L;    -   a corrosion inhibitor at a concentration from about 0.01 g/L to        about 20 g/L;    -   a surface active agent at a concentration of 0.02 g/L to 2 g/L;    -   an oxygen scavenger at a concentration from about 0.05 g/L to        about 10 g/L;    -   a reducing agent at a concentration from about 0.1 g/L to about        10 g/L, the reducing agent having substantially no oxygen        scavenging properties; and    -   a water soluble solvent at a concentration from about 10 g/L to        about 100 g/L.

Another embodiment of the present invention is a cleaning solution foran integrated circuit substrate. The cleaning solution comprises anamine to provide a pH for the cleaning solution of 7 to 13 and allvalues and subranges subsumed therein, a complexing agent, a corrosioninhibitor, a surface active agent, an oxygen scavenger, a reducingagent, and a water soluble solvent. Each of the components of thesolution and amounts of each of the components are included so as tomake the cleaning solution effective for cleaning the integrated circuitsubstrate. Additional description of properties and compounds forcomponents of the solution for embodiments of the present invention arepresented supra.

Reference is now made to Table 1 where there is shown a summary ofsolution compositions for embodiments of the present invention andresults for seven experiments using the solution compositions. Thesolutions were used to clean substrate surfaces having a cap layercomprising a cobalt tungsten phosphorous composite. The cleaning stepwas done at about room temperature. The surfactant Triton X-100® is aregistered trademark of Union Carbide and has the chemical formula(C₁₄H₂₂O(C₂H₄O)_(n)). The etch rates of the cap are low and meet therequirements for manufacturing operations.

In the foregoing specification, the invention has been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the present invention as set forthin the claims below. Accordingly, the specification and figures are tobe regarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope of thepresent invention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any element(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature or element of any or all the claims.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having,” “at least one of,” or any other variationthereof, are intended to cover a non-exclusive inclusion. For example, aprocess, method, article, or apparatus that comprises a list of elementsis not necessarily limited only to those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

TABLE 1 Amine 2 (to CoWP adjust Complexing Oxygen Reducing etch Example# Amine 1 pH) agent Inhibitor scavenger agent Surfactant Solvent pH in30 min/A 1 2 g/L TMAH 10.7 1 hydroxyl- amine 2 5 g/L TMAH 1 g/L boric10.7 3 diethanol- acid amine 3 5 g/L TMAH 1 g/L boric 0.5 g/L 10.7 3diethanol- acid Triton X- amine 100 ® 4 5 g/L TMAH 2 g/L citric 2 g/L 111 diethanol- acid L- amine Ascorbic acid 5 5 g/L TMAH 2 g/L citric 2 g/L10 g/L 11 1 diethanol- acid L- isopro- amine Ascorbic panol acid 6 5 g/L2 g/L 1.2 g/L 10.7 0 diethanol- L- Dimethyl- amine Ascorbic amine acidborane 7 5 g/L TMAH 2 g/L 1 g/L 0.5 g/L 10.7 5 diethanol- Glycolicbenzotriazole- Triton X- amine acid 5- 100 ® carboxylic acidTMAH—tetramethylammonium hydroxide

1. A method of cleaning a substrate having copper and dielectricdamascene metallization, the surface of the copper having a cap ofcobalt, cobalt alloy, nickel, nickel alloy, or cobalt-nickel alloy film,the method comprising: applying a cleaning solution to the substrate toremove at least one of defects and contamination with negligibledissolution of the cap, the solution comprising one or more amines, atleast one of the one or more amines providing a pH from 7 to about 13 inthe cleaning solution. 2-34. (canceled)
 35. A method of fabricating anintegrated circuit, the method comprising: providing a substrate havinga metal and dielectric damascene metallization layer; using electrolessdeposition to deposit substantially on the metal a cap comprising atleast one of the chemical elements cobalt and nickel; cleaning thesubstrate after deposition of the cap with a cleaning solutioncomprising an amine to provide a pH for the cleaning solution of 7 to 13and all values and subranges subsumed therein.
 36. The method of claim35, wherein the cleaning solution further comprises one or morecomplexing agents, and at least one of the one or more complexing agentsis a non-amine.
 37. The method of claim 36, wherein the cleaningsolution further comprises at least one corrosion inhibitor.
 38. Themethod of claim 36, wherein the cleaning solution further comprises atleast one oxygen scavenger to provide a lower concentration of dissolvedoxygen in the cleaning solution.
 39. The method of claim 36, wherein thecleaning solution further comprises at least one reducing agent; theleast one reducing agent being substantially incapable of scavenging fordissolved oxygen.
 40. The method of claim 37, wherein the cleaningsolution further comprises at least one oxygen scavenger so as to lowerthe concentration of dissolved oxygen in the cleaning solution.
 41. Themethod of claim 37, wherein the cleaning solution further comprises atleast one reducing agent; the at least one reducing agent beingsubstantially incapable of scavenging for dissolved oxygen.
 42. Themethod of claim 38, wherein the cleaning solution further comprises oneor more reducing agents; the one or more reducing agents beingsubstantially incapable of scavenging for dissolved oxygen.
 43. Themethod of claim 42, wherein the cleaning solution further comprises oneor more corrosion inhibitors to protect the cap or retard thedissolution of the cap in the cleaning solution.
 44. The method ofclaims 35, wherein the cleaning solution further comprises one or moresurface active agents so as to provide adequate wetting of thesubstrate.
 45. The method of claim 35, wherein the cleaning solutionfurther comprises one or more water soluble solvents.
 46. The method ofclaim 35, wherein the concentration of the amine is from about 1 g/L toabout 100 g/L.
 47. The method of claim 36, wherein the amine is selectedfrom the group consisting of primary alkylamines, secondary alkylamines,tertiary alkylamines, quaternary alkylamines, primary arylamines,secondary arylamines, tertiary arylamines, quaternary arylamines,ammonia, primary alkanolamines, secondary alkanolamines, tertiaryalkanolamines, ethanolamine, diethanolamine, triethanolamine, choline,amines with mixed alkyl and alkanol functionalities,tetramethylguanidine, and hydroxylamine.
 48. The method of claim 37,wherein the at least one complexing agent concentration is from about0.5 g/L to about 50 g/L.
 49. The method of claim 36, wherein the atleast one complexing agent concentration is a value from about 0.5 g/Lto about 50 g/L, and the at least one complexing agent is selected fromthe group consisting of carboxylic acids, hydroxycarboxylic acids, aminoacids, phosphonic acid, phytic acid, and organic acids where Ig K forCoL>2.
 50. The method of claim 37, wherein the corrosion inhibitorconcentration is between 0.01 g/L to 20 g/L.
 51. The method of claim 37,wherein the corrosion inhibitor is selected from the group consisting oftriazole, benzotriazole, methyl-benzotriazole, carboxy-benzotriazole,hydroxybenzotriazole, thiazole, mercaptobenzothiazole,polyvinylpyrrolidone, polyvinylalcohol, polyalkylimines,polyethylenimines, long chain alkylamines, tetrazoles, orthophosphates,metaphosphates, phosphites, phosphonates, silicates, alkylphosphonates,alkoxysilanes, nitrites, and bicyclohexylammonium nitrite.
 52. Themethod of claim 38, wherein the oxygen scavenger concentration isbetween 0.05 g/L to 10 g/L.
 53. The method of claim 38, wherein theoxygen scavenger is selected from the group consisting of hydroxylamine,diethylhydroxylamine, methyl-ethylketoxime, carbohydrazide, L-ascorbicacid, D-ascorbic acid, derivatives of ascorbic acid, chlorogenic acid,hydrazine, hydrazine salts, derivatives of hydrazine, caffeic acid,phytic acid, luteolin, and sulfites.
 54. The method of claim 39, whereinthe reducing agent concentration is between 0.1 g/L to 10 g/L.
 55. Themethod of claim 39, wherein the reducing agent is selected from thegroup consisting of boron containing reducing agents, hypophosphites,thiosulfite, and aldehydes.
 56. The method of claim 35, wherein thecleaning solution further comprises a corrosion inhibitor present in aconcentration between about 0.01 g/L to about 10 g/L and an oxygenscavenger present in a concentration between about 0.05 g/L to about 10g/L.
 57. The method of claim 41, wherein the at least one corrosioninhibitor concentration is between about 0.01 g/L to about 20 g/L andthe at least one reducing agent concentration is between about 0.1 g/Lto about 10 g/L.
 58. The method of claim 42, wherein the oxygenscavenger concentration is between about 0.05 g/L to about 10 g/L andthe reducing agent concentration is between about 0.1 g/L to about 10g/L.
 59. The method of claim 43, wherein the corrosion inhibitorconcentration is between about 0.01 g/L to about 20 g/L, the at leastone oxygen scavenger concentration is between about 0.05 g/L to about 10g/L, and the at least one reducing agent concentration is between about0.1 g/L to about 10 g/L.
 60. The method of claim 35, wherein thecleaning solution further comprises at least one surface active agentpresent in a concentration of about 0.02 g/L to about 2 g/L for each ofthe at least one surface active agent and the at least one surfaceactive agent is anionic, cationic, nonionic, amphoteric, or mixturesthereof.
 61. The method of claim 35, wherein the cleaning solutionfurther comprises at least one water soluble solvent present in aconcentration from about 10 g/L to about 100 g/L.
 62. The method ofclaim 35, wherein the cleaning solution further comprises at least onewater soluble solvent comprising primary alcohols, secondary alcohols,tertiary alcohols, polyols, ethylene glycol, dimethylsulfoxide, orpropylenecarbonate. 63-64. (canceled)
 65. The method of claim 35,further comprising applying the cleaning solution to the substrate witha brush.
 66. The method of claim 35, further comprising cleaning thesubstrate with the cleaning solution at a temperature in the range fromabout 5° C. to about 90° C.